95MP cameraThomas Zurbuchen from NASA's Science Mission Directorate said in an administration release that Kepler had "wildly exceeded" expectations, and paved the way for the future search for extra-terrestrial life. "Its discoveries have shed a new light on our place in the universe, and illuminated the tantalising mysteries and possibilities among the stars". Without fuel, the Kepler team has chose to retire the spacecraft, though it will continue to drift along in orbit around Earth for the foreseeable future. That means that we don't have to worry about it crashing down into someone's barn in Wyoming, but the statement doesn't actually say what will happen to the dead telescope. The US space agency said this brings an end to a prolific nine-and-a-half year mission in which it discovered over 2,600 intriguing exoplanets, some of which may harbour life.

"We know the spacecraft's retirement isn't the end of Kepler's discoveries", said Jessie Dotson, Kepler's project scientist at NASA's Ames Research Centre in California's Silicon Valley. As an astronomical passing of the baton, in the last month of Kepler's mission, both TESS and Kepler simultaneously observed over a hundred of the same stars.

Kepler searched for alien worlds by looking out for their transits, which are dips in the brightness of stars that could indicate orbiting planets.

NASA's elite planet-hunting spacecraft has been declared dead, just a few months shy of its 10th anniversary.

NASA astrophysics director Paul Hertz estimated that anywhere from two to a dozen of the planets discovered by Kepler are rocky and Earth-sized in the so-called Goldilocks zone - the habitable area around a star where the temperature would permit existence of liquid water.

Engineers found out earlier this year that Kepler was nearly out of fuel. Now, Nasa's hashtag "moreplanetsthanstars" says it all: the universe is home to more planets than stars, with billions of potentially habitable planets just in our own galaxy.

Kepler was launched in March 2009 with enough fuel to keep it going for at least six years, according to The Verge.

"Basically, Kepler opened the gate for mankind's exploration of the cosmos", William Borucki, Kepler's now-retired chief investigator, told reporters.

And even though TESS will collect fresh data, Kepler's work still isn't done.

The far more advanced James Webb Space Telescope, scheduled to lift off in 2021, should be able to reveal more about planets' mass, density and the makeup of their atmosphere - all clues to habitability. "We expected to find more Jupiters", but instead the most common size is between that of Earth and Neptune, of which there are none in our solar system.

In the course of its decade, Kepler discovered some 5,580 possible planets by staring intently at the stars in a tiny patch of the Milky Way.